My sister has it and watches a lot of Netflix - I'm not impressed to be honest. The selection from Netflix is abysmal and I am led to believe from Roku themselves that because of some interface problem, you don't see all the content that you would see via your computer. Something about an SDK not supporting all the features....
There are other movie services but these are worse than Netflix.
The majority of the other channels are paid for and I wouldn't bother. Get XBMC on a Rasberry Pi and a HP N40L microserver for your NAS.